Non diffusion fuel cell and a process of using the fuel cell

ABSTRACT

A fuel cell having an anode immersed in an electrolyte in an anode tank, and a cathode immersed in the electrolyte in the cathode tank, and the anode and the cathode connected to an external electrical load. Fuel is supplied to the anode tank and an oxidant to the cathode tank. Each electrode is a monolithic electrode, a composite electrode, or an internally coupled electrode having a catalyst surface. There may be an external reaction vessel for processing electrolyte before returning it to the tanks and conditioning and recycling of fuel. The impedance of the fuel cell is reduced substantially over fuel cells having an electrical path through the solution.

FIELD OF INVENTION

This invention relates to electrical fuel cells.

BACKGROUND

The applicant has applied for a patent with Application NumberPCT/AU97/00488 for a FUEL CELL AND A PROCESS OF USING A FUEL CELL underthe Patent Cooperation Treaty. The patent was published on Feb. 12, 1998with Publication Number WO 98/06145.

The above fuel cell consisted of a separate anode cell and a separatecathode cell with two electrodes in each cell adjacent to each other.Fuel is fed into the anode cell and oxidant is fed into the cathodecell. Ions produced in one cell are transported to the other cell toprovide the ion transfer for the fuel cell reactions. The electroniccircuit is completed through the load, the connection of the oneelectrode in the anode cell to another electrode in the cathode cell byan external conductor, and through the electrolyte between the adjacentelectrodes at the anode cell and at the cathode cell.

This fuel cell eliminated the diffusion of ions through a media commonto prevailing conventional fuel cells such as the proton electrolyticmembrane fuel cell, the molten carbonate fuel cell, and the solid oxidefuel cell. The fuel cell not only reduced the high impedance common toconventional fuel cells but the simple and relatively low temperature ofoperation allowed for low cost construction of the fuel cell usingavailable materials and hardware.

This simple fuel cell can be built in much larger sizes thanconventional fuel cells.

PRIOR ART

The conventional fuel cells, namely the proton electrolytic membranefuel cell, the molten carbonate fuel cell, and the solid oxide fuel celland their operating principles were described in PCT/AU97/00488 and willnot be repeated in this patent application. The fuel cell covered inPCT/AU97/00488 is a major improvement over conventional fuel cells;however, there is further room for improvement as the electronic circuithad to pass through the electrolyte between the adjacent electrodes atthe anode cell and again at the cathode cell. While this impedance maynot be as great as conventional fuel cells, it was desirable to removethis impedance if possible and make the electronic circuit independentof the conductivity of the electrolyte. It would then be possible to useless corrosive electrolytes and also the possibility of using gases toconduct the ions between the anode cell and the cathode cell. Thisfeature would also result in a higher fuel cell efficiency and higherpower density.

It is the object or one of the objects of this invention to provide suchan improved fuel cell.

DESCRIPTION OF THE INVENTION

In one form therefore the invention is said to reside in a fuel cellcomprising a separate anode cell and a separate cathode cell, the anodecell including an anode tank for containing an electrolyte and having ananode electrode immersed therein, means to supply electrolyte to theanode tank and means to supply fuel to the anode tank, the cathode cellincluding a cathode tank for containing the electrolyte and having acathode electrode immersed therein, means to supply electrolyte to thecathode tank and means to supply an oxidant to the cathode tank, meansto withdraw reacted electrolyte from the anode tank and to supply it tothe cathode tank, means to withdraw reacted electrolyte from the cathodetank and supply it to the anode tank, each of the anode electrode andthe cathode electrode having a central current collector and a coatingof catalyst thereon, each of the anode electrode and the cathodeelectrode having a first end and a second end, means to connect thefirst end of the anode electrode and the first end of the cathodeelectrode to a first electrical load outside of the fuel cell, and meansto connect the second end of the anode electrode to the second end ofthe cathode electrode to a second electronic load as part of a completeelectrical circuit of the fuel cell.

In one embodiment the second electrical load may comprise an ionic orsemiconductor membrane or a diode device.

Each of the anode electrode and cathode electrode may have a compositecubical or cylindrical construction comprising an outer conductorcurrent collector or collectors and a catalyst coating applied to its ortheir surfaces and an inner current collector electrically connected tothe two outer conductor current collectors through an ionic orsemiconductor membrane wherein the outer conductor current collector orcollectors comprise the first end of the respective electrode and theinner current collector comprises the second end of the respectiveelectrode.

To achieve the highest power output from the fuel cell the electricalloads may be connected to either the outer conductor current collectoror collectors or the inner current collector depending on the specificionic reactions occurring at each electrode.

Alternatively the respective inner current collectors may be connecteddirectly together with the ionic or semiconductor membranes between therespective inner current collectors and outer conductor currentcollector or collectors providing the second electrical load.

In another embodiment the anode tank and the cathode tank may beseparated by a common wall and the central collector of the anodeelectrode and the cathode electrode partially or completely connectedthrough the common wall by an ionic or semiconductor membrane or a diodedevice providing the second electrical load.

In one preferred embodiment the means to supply electrolyte to the anodetank comprises the means to withdraw electrolyte from the cathode tankand the means to supply electrolyte to the cathode tank comprises themeans to withdraw electrolyte from the anode tank.

There may be further included a reaction tank and wherein the respectivemeans to supply electrolyte to the anode tank and to the cathode tankcomprises means to withdraw electrolyte from the reaction tank and therespective means to withdraw reacted electrolyte from the anode tank andfrom the cathode tank transfers reacted electrolyte to the reactiontank.

There may be further included means for recovering excess fuel from thereacted electrolyte discharged from the anode cell and a means ofremoving reaction products from the anode tank, the cathode tank, or thereaction tank.

The anode tank and the cathode tank may be constructed to provide anefficient contact between the electrolyte containing the fuel or oxidantand the electrodes immersed in the electrolyte.

The anode electrode and the cathode electrode may be made from amaterial selected from the group comprising solid, porous, fibre, gauze,tiny particles of various shapes, or woven cloth of metal or alloys ofmetals, carbon, vitreous carbon, conducting plastics material or aslurry comprising fine particles comprising catalyst or coated withcatalyst fluidised in the respective tanks.

The anode electrode and the cathode electrode may be electroplated,sputtered or coated with the catalyst selected from platinum, nickel,cobalt, lithium, lanthanum, strontium, palladium, rhodium, yttrium, orany mixtures of these.

The liquid electrolyte may be selected from the group comprising acidicelectrolytes including sulphuric acid, phosphoric acid, methanesulphonic acid, other organic and inorganic acids, alkaline electrolytesincluding sodium hydroxide, potassium hydroxide, molten electrolytesincluding lithium-potassium carbonate, and mixtures of electrolyte andcolloids or fine solid catalyst or fine particles coated with catalystbeing a catalyst for the anode reaction and the cathode reaction.

Characteristics of the electrolyte may be altered by the addition ofmodifiers either as ions or colloids such as surfactants and metal ionssuch as vanadium oxide.

The electrolyte may be a gas selected from the group comprisingnitrogen, helium, argon, or mixtures of these gases and other gases suchas carbon oxides.

The fuel may be selected from the group comprising hydrogen, natural andrefined hydrocarbons such as methane, propane, butane, liquidhydrocarbons, methanol, ethanol and other alcohols, and natural andmanufactured carbohydrates such as biomass gas.

When the fuel is a hydrocarbon there may be further included means ofcracking the hydrocarbon fuel or means of forming hydrogen fromhydrocarbon fuels before introducing the fuel into the anode tank.

Where the fuel is a hydrocarbon there may be further included means tocondition the hydrocarbon fuel prior to direct feeding to the fuel cell,the means to condition selected from pyrolysis with or withoutcatalysis, contacting with a catalyst, contacting with a super acid orzeolite, or subjecting the hydrocarbon fuel to electromagnetic energy.

The oxidant may be selected from the group comprising air, oxygen,oxygen-nitrogen mixtures, oxygen-carbon oxide mixtures, hydrogenperoxide, and potassium permanganate.

There may be further included means for intermittent injection ofgaseous fuel or oxidant respectively into the anode or cathode tanks.

Also there may be further included means to heat or cool the anode tank,or the cathode tank, or the reaction tank to a selected temperature andmeans to raise and maintain the pressure in the anode tank, or thecathode tank, or the reaction tank to a selected pressure.

In an alternative embodiment the invention may reside in a battery offuel cells comprising a plurality of fuel cells as discussed abovewherein the anode electrodes and the cathode electrodes of adjacentcells are electrically connected in series or in parallel.

In an alternative embodiment the invention may reside in a fuel cellhaving of a separate anode cell and a separate cathode cell and areaction tank wherein: the anode cell comprises an anode tank having ananode electrode immersed therein, the anode electrode being selectedfrom a monolithic electrode, a composite electrode, or an internallycoupled electrode, means to supply electrolyte to the anode tank fromthe reaction vessel, means to supply fuel in the form of gas, liquid, orsolid mixed with the electrolyte being supplied to the anode tank, thecathode cell comprises a cathode tank having a cathode electrodeimmersed therein, the cathode electrode being selected from a monolithicelectrode, a composite electrode, or an internally coupled electrode,means to supply electrolyte to the cathode tank from the reaction tank,means to supply air, oxygen, oxygen-nitrogen mixtures, or other oxidantsmixed with the electrolyte to the cathode tank, means to withdrawreacted electrolyte from the anode tank and deliver to the reactiontank, means to withdraw reacted electrolyte from the cathode tank anddeliver to the reaction tank, each of the anode electrode and thecathode electrode having a first end and a second end, means to connectthe first end of the anode electrode and the first end of the cathodeelectrode to a first electrical load outside of the fuel cell, and meansto connect the second end of the anode electrode to the second end ofthe cathode electrode to a second electrical load as part of a completeelectrical circuit of the fuel cell.

In an alternative embodiment the invention may reside in continuousprocess for producing electric power and heat in a fuel cell fromreacting a fuel in an anode tank and an oxidant in a cathode tank, thefuel cell having an anode electrode immersed in the electrolyte in theanode tank, and a cathode electrode immersed in the electrolyte in thecathode tank and the anode electrode and the cathode electrode connectedto a first electrical load at one end thereof and connected a secondelectrical load at another end thereof, the process comprising the stepsof; introducing the fuel with the electrolyte in the anode tank whereina catalyst on the anode electrode in the anode tank causes a chemicalreaction or ionises the fuel thereby which producing electrons,transferring the electrons through an external electrical circuitthrough the external electrical loads to the cathode electrode,introducing the oxidant mixed with the electrolyte into the cathode tankwherein a catalyst on the cathode electrode causes a chemical reactionor ionises the oxidant with the electrons from the anode, and completingthe electronic circuit.

The ions produced at the anode electrode required for the reaction atthe cathode electrode may be delivered continuously through theelectrolyte and the ions produced at the cathode electrode required forreactions at the anode electrode may be delivered continuously throughthe electrolyte.

This embodiment of the invention may further include a step oftransferring the electrolyte from the anode tank and from the cathodetank to a reaction tank and transferring the electrolyte from thereaction tank to the anode tank and to the cathode tank and wherein theions produced at the anode electrode and the ions produced at theelectrode cathode are delivered continuously through the electrolyte toa reaction tank.

This embodiment of the invention may further include the step ofrecycling excess fuel exiting from the anode tank.

This embodiment of the invention may further include the step ofremoving the reaction products such as water or carbon dioxide from theelectrolyte in an evaporating tank, vacuum vessel, or an absorptionvessel.

This embodiment of the invention may further include a step of injectinggaseous fuel to the anode in a cyclic manner and injecting gaseousoxidant into the cathode tank in a cyclic manner.

The anode tank, the cathode tank, and the reaction tank may be heated orcooled and pressurised.

The oxidant, the electrolyte and the fuel may be as discussed above.

The fuel may travels co-current or counter-current to the electrolyte inthe anode tank and the oxidant travels co-current or counter-current tothe electrolyte in the cathode tank.

There may be several anode electrodes of the same type in one anode tankand correspondingly several cathode electrodes of the same type in onecathode tank. These electrodes may be electrically connected singly orin groups in series or in parallel. The optimum electrical connection ofthe electrodes depends on the catalyst and the electrolyte used butshould naturally result in the highest voltage or power production fromthe fuel cell.

The electrode shape may be cubical, cylindrical, tube like or anygeometrical shape and the electrodes may be installed along the flow oracross the flow of the electrolyte.

In terms of electrolyte flow, several anode tanks may be connectedsingly or in groups in series or in parallel to a corresponding numberof cathode tanks.

There may be further means to vary the ratio of the fuel and oxidant tothe electrolyte fed into the anode tank and to the cathode tank and anadditional means to add gas fuels in cyclic amounts to the anode tank.

The monolithic anode electrode and the monolithic cathode electrode maybe made from materials selected from the group solid, porous, fibre,gauze, or woven cloth of metal, carbon, graphite, vitreous carbon, finevitreous carbon beads, conducting plastics material, or a slurrycomprising catalyst or fine particles coated with catalyst fluidised inthe respective anode tank and cathode tank.

The composite anode electrode and the composite cathode electrode may bemade from the same material as the monolithic electrode. Thesemiconductor or ionic membrane between the electrodes should allow theflow of electrons only in one direction and may be made from a range ofmaterials such as plastics, ceramics, oxides and crystals.

The monolithic and the composite anode electrode and cathode electrodemay be coated with catalyst by using with conductive binders orelectroplating or by sputtering with catalyst selected from platinum,nickel, cobalt, lithium, lanthanum, strontium, palladium, yttrium, orany mixtures of these materials and their compounds.

The gaseous electrolyte may be selected from gases such as nitrogen,helium, argon, and compounds containing carbon and or hydrogen oroxygen.

The electrolyte may contain activators and modifiers as ions or fineparticles or coatings of fine particles such as oxides of vanadium,potassium, and modifiers such as ionic and non-ionic surfactants toimprove the efficiency of the fuel cell.

The ions produced at the anode required for the cathode reaction aredelivered continuously by the electrolyte to the cathode tank.

The order of reactions may be true for a combination of catalyst andelectrolyte but the reactions may vary with other combinations ofcatalyst and electrolyte.

For instance in a fuel cell using hydrogen for fuel and oxygen foroxidant and concentrated phosphoric acid for electrolyte, the reactionsare:

Anode Reaction H₂→2H(+)+2e(−)

Cathode Reaction 1/2O₂+2H(+)+2e(−)→H₂O

The fuel cell reactions using hydrogen for fuel and oxygen for oxidantin a concentrated potassium hydroxide electrolyte are:

Anode Reaction H₂+2OH(−)→2H₂O+2e(−)

Cathode Reaction 1/2O₂+H₂O+2e(−)→2OH(−)

There may be further included the step of removing the fuel cellreaction products such as water and carbon dioxide from the reactedelectrolyte in an evaporating vessel, a vacuum vessel, or an absorptionvessel.

The process may be carried out in pressures from sub-atmospheric to5,000 pounds per square inch and at temperatures from sub-zerotemperatures to 1200° C.

Heat produced from the fuel cell reaction may be may be recovered forco-generation, industrial heating, and domestic heating.

The fuel may travel co-current or counter-current to the electrolyte inthe anode tank and the oxidant may travel co-current or counter-currentto the electrolyte in the cathode tank.

Hence it will be seen that this invention is a chemico-electricalprocess to collect the electrical power and heat from the reaction ofthe fuel and oxidant. The process is carried out in a separate anodecell where fuel and electrolyte is introduced and a separate cathodecell where the oxidant and electrolyte is introduced. A completeelectrical circuit is established between the anode electrode, theexternal electrical load, and the cathode electrode. Ion transportwithin the fuel cell is accomplished by circulating the liquid or gaselectrolyte between the anode cell and the cathode cell.

BRIEF DESCRIPTION OF THE DRAWINGS

This generally describes the invention but to assist with understandingof the invention reference will now be made to preferred embodiments ofthe invention as illustrated in the following drawings and experimentalwork carried out with experimental fuel cells according to theinvention.

In the drawings:

FIG. 1 shows a cross sectional view of a monolithic electrode accordingto one embodiment of the invention,

FIG. 2 shows a cross sectional view of a composite electrode accordingto an alternative embodiment of the invention,

FIG. 3 shows a schematic view of a fuel cell with internally coupledelectrodes according to one embodiment of the invention,

FIG. 4 shows a schematic view of a fuel cell with series flow ofelectrolyte according to an alternative embodiment of the invention,

FIG. 5 shows a schematic view of a fuel cell with parallel flow ofelectrolyte according to an alternative embodiment of the invention,

FIG. 6 shows a schematic view of a fuel cell incorporating U-shapedmonolithic electrodes shaped to provide an electrical connection only tothe dry end of the anode and cathode tank,

FIG. 7 is a diagram showing the experimental series flow apparatus builtto develop this invention, and

FIG. 8 is a diagram showing one manner of stacking or series connectionof two fuel cells according to this invention based on experimentalresults.

Now looking more closely at the drawings and referring to FIG. 1, itwill be seen that in cross section the monolithic electrode isconstructed of a catalyst coating 1 connected to a current collector 2and the current produced is conducted by copper wire 3. The currentcollector 2 extends beyond each end of the catalyst coating 1 and copperwire 3 extends from each end of the current collector 2 and may beconnected to an electrical load.

In FIG. 2, it will be seen that in cross section the composite electrodeis made up of a catalyst coating 4 connected to a current collector 5which conducts the electrons produced or required by the fuel cellreaction at the catalyst coating. The copper wire 8 conducts theelectrons to the outer circuit. The central conductor 7 provide themeans to complete the electronic circuit and is connected to conductor 5by means of ionic or semiconductor membrane 6. This type of electrode isused at both the anode and the cathode in place of the monolithicelectrode. The external electrical connection may vary depending on thecatalyst and the electrolyte, for instance, 9 of the composite anodeelectrode may be connected to 9 of the composite cathode electrode andthe electrical load connected between 8 of the composite anode electrodeand 8 of the composite cathode electrode.

In FIG. 3 it will be seen in cross section that internally coupledelectrodes are installed in a fuel cell. The anode tank 10 and cathodetank 9 have an anode and cathode respectively and are separated by awall 11. The catalyst coating 12 may be different for each electrode.The current collectors 13 are connected through the wall 11 by an ionicor semiconductor membrane 14. The electronic circuit is completed byconnecting the terminals 15 to the electrical load. The ionic membraneconnection may occupy part or all of the length of the currentcollectors 13. There may be several sets of the composite electrodes inone fuel cell connected in series or parallel.

The series fuel cell in FIG. 4 shows a separate anode cell 22 and aseparate cathode cell 16 each containing an electrode 17. This electrode17 may either be a monolithic or composite electrode. The electronsproduced at or consumed at the catalyst surface of the electrodes areconducted through the electrical loads 20 and 21. The ions produced atthe anode cell 22 are transported by the electrolyte by stream 18 whilethe reacted electrolyte is returned from the cathode cell 16 to theanode cell 22 by stream 19. This arrangement provides a continuoussystem for the fuel cell. For simplicity of this diagram, auxiliariessuch as means to remove excess fuel from the anode and recycle this tothe anode fuel feed and the means to remove reaction products from theelectrolyte stream are not shown in FIG. 4.

The parallel fuel cell shown on FIG. 5 shows a separate anode cell 32and a separate cathode cell 33 containing respective electrodes 24. Theelectrons generated at the anode electrode are conducted to theelectrical loads 25 and 26. The ions produced by the anode reactions areconveyed continuously by stream 27 to the reaction tank 29. Similarly,stream 28 conveys continuously the ions produced in the cathode reactionto reaction tank 29. The ions react in the reaction tank 29 and theneutralised electrolyte is returned to the anode cell by stream 30 andto the cathode cell by stream 31. An advantage of this parallelarrangement is that heat from the fuel cell reaction would be moreconvenient to apply to co-generation. Excess reactants and by-productsmay be removed from reaction tank 29 in stream 34.

FIG. 6 shows a U-shaped monolithic electrode 40 installed in a seriestype fuel cell. The catalyst coating 41 and the current collector 42 areU-shaped to allow the external electrical connections to the electricalloads 44 and 46 to be on the gas side of the fuel cell tank. Insulationor a baffle 48 may be required between the catalyst coating depending onthe gap and the nature of the electrolyte and the catalyst. Fuel is fedin by line 56 to the anode cell and oxidant is fed in line 57 to thecathode tank. Pump 58 provides the means to cycle electrolyte from theanode tank to the cathode tank through line 61 and pump 59 provides themeans to cycle electrolyte from the cathode tank to the anode tankthrough line 63.

Unreacted fuel and reacted electrolyte is removed from the anode cellthrough line 50 and to separator 52. In the separator 52 unreacted fuelis removed from the stream and recycled in line 54 to fuel conditioner55. In fuel conditioner 55 new fuel and recycled fuel is modifiedprocesses such as pyrolysis with or without catalysis, contacting with acatalyst, contacting with a super acid or zeolite, or subjecting thehydrocarbon fuel to electromagnetic energy and then the conditionedfuels is fed into the anode cell by fuel inlet 56. Excess oxidant,electrolyte and waste products are removed in line 60 from the cathodetank and separated in separator 62 with electrolyte being returned tothe cathode tank and waste and oxidant be removed in line 64

FIG. 7 is a schematic diagram of the series type fuel cell testapparatus.

The fuel cell has an anode tank 70 and a cathode tank 72 and a sump 74.Electrolyte flows by gravity from the cathode tank 72 over weir 76 tothe anode tank 70. Electrolyte then flows by gravity from the anode tank70 over weirs 82 and 83 to the sump 74. From there electrolyte isremoved in line 81 and pumped by pump 84 to the cathode tank 72. Oxygenis introduced through line 77 to a pipe mixer 78 and then transferred byline 75 to the cathode tank 72 while hydrogen is introduced to the anodetank 70 through line 80. The electrodes are constructed with a carboncloth surface painted with a mixture of black platinum and an organicbinder 86 as the catalyst and are connected to an expanded metal niobiumcoated with platinum current collector 88. The electrolyte used was 40%KOH in aqueous solution. This apparatus produced only a low powerdensity but was adequate to demonstrate the operating principle of thefuel cell.

A diagram showing one method of stacking two fuel cells is shown on FIG.8. The stacking shows the total voltage is equal to the sum of thevoltage generated from each fuel cell. As discussed previously, otherstacking connections are possible and may prove more appropriate whenfuel cells of higher power density are used.

Experimental Data

A diagram of the large scale laboratory apparatus built to develop thisinvention is shown on FIG. 7. Testing was carried out at atmosphericpressure and the cell and gas mixer were provided with electric heatersto heat the electrolyte.

The electrodes are commercially available and consist of an expandedmetal niobium coated with platinum current collector sandwiched betweencarbon cloth. The carbon cloth was coated with a mixture of an organicbinder and platinum black at a loading of about 0.5 mg/cm2. Copper wireswere welded to the niobium current collector at both ends of theelectrode and then coated with epoxy. The electrode measured about 50mm×200 mm×1.9 mm thick.

The fuel cell tanks were made from 6 mm thick polypropylene sheet. Theelectrolyte used was 40 percent (w/w) potassium hydroxide and wascirculated at the rate of about 1,200 mls per minute by a MasterflexEasy Load tube pump. Oxygen flow rate to the cathode tank was 78 mls perminute while the hydrogen feed rate at the anode tank was 100 mls perminute. Due to the low power output of the electrodes, the resistance ofthe voltmeters of about 8 to 10 megaohms (METEX Model M-3850-D and DickSmith Q-1570) were used as the electrical load in the experiments.

Referring to FIG. 7, when a copper wire which has practically noresistance connects (B) to (D), the voltage between (A) and (C) is zero.Likewise, the voltage of the cell is zero when (B) is connected to (C);or (A) to (D); or (A) to (C). This suggests that the electrodes arebeing short-circuited and the power is drained completely.

At 25° C., when the voltmeter was connected between (A) and (C) andanother voltmeter was connected between (B) and (D), the voltmeterreadings were:

(A) to (C)=542 millivolts

(B) to (D)=542 millivolts

A similar voltage is generated between a copper wire connecting (A) to(B) and a copper wire connecting (C) to (D). This observation may allowa single electrical load to be connected to this fuel cell when usingthe monolithic electrodes.

When the current meter which has a resistance of about 3 ohms wasconnected across (A) and (C), the current stabilised at 19.2milliamperes and 29 millivolts.

At 31 degrees Celsius electrolyte temperature, the readings of thevoltages were:

(A) to (C)=260 millivolts

(B) to (D)=260 millivolts

With the experiments carried out at atmospheric pressure, it is believedthat the solubility of the gases reduced with higher temperatureresulting in reduced power output of the fuel cell. This indicates theimportance of pressure on the power output of the fuel cell.

This arrangement of electrodes and electrolytes produced fuel cell typereactions. It is possible to include the other concepts of electrodeconstructions such as the composite electrode based on theseexperimental results. The single electrical load to the fuel cell may beattained by using conventional means such as incorporating a diode orsimilar device in the electrical circuit, or this problem may beresolved in the series connection or stacking of the fuel cells.

The most important result of these experiment is that the fuel cellconcept generated fuel type reactions in a continuous system.

The “stacking” or series connection of fuel cells to obtain workingvoltages for commercial applications is critical for any fuel cellproposal. Two identical series type fuel cells using the best of theremaining platinum electrodes were constructed using the same pumpingarrangements. FIG. 8 is a schematic diagram of the electrodeconnections.

At 24 degrees Celsius and using 40% potassium hydroxide electrolyte,hydrogen fuel, and oxygen as oxidant, the voltages obtained were:

Cell 1 (1A) to (1C)=609 millivolts

Cell 2 (2A) to (2C)=926 millivolts

Total Voltage=1,535 millivolts

It is believed that the contact between the catalyst layer and theniobium collector is being degraded by the electrolyte based onobservation of the electrodes. This would explain the difference involtage produced by Cell 1 and Cell 2.

When (1C) is connected to (2E) and (2A) is connected to (1F), thevoltage measured between:

(1E) and (2C)=1,534 millivolts, and

(1A) and (2F)=1.523 millivolts

The experiment confirms that the fuel cell of this invention can bestacked to produce higher working voltages.

Other series connections were trialed during the experiment but producedlower voltages. For instance, connecting 1C to 2F; 1A to 2E; and 1F to2A produced a voltage of 1,369 millivolts between 1E and 2C. It ispossible that when higher power densities are used in this fuel cellthat the optimum stacking connection may be different to that shown onFIG. 8.

Throughout this specification and the claims that follow unless thecontext requires otherwise the terms “comprise” and “include” andvariations such as “comprising” and “including”, will be understood toimply the inclusion of a stated integer or group of integers but not tothe exclusion of any other integer or group of integers.

What is claimed is:
 1. A fuel cell comprising a separate anode cell anda separate cathode cell, the anode cell including an anode tank forcontaining an electrolyte and having an anode electrode immersedtherein, means to supply electrolyte to the anode tank and means tosupply fuel to the anode tank, the cathode cell including a cathode tankfor containing the electrolyte and having an cathode electrode immersedtherein, means to supply electrolyte to the cathode tank and means tosupply an oxidant to the cathode tank, means to withdraw reactedelectrolyte from the anode tank and to supply it to the cathode tank,means to withdraw reacted electrolyte from the cathode tank and tosupply it to the anode tank, each of the anode electrode and the cathodeelectrode having a central current collector and a coating of catalystthereon, each of the anode electrode and the cathode electrode having afirst end and a second end, means to connect the first end of the anodeelectrode and the first end of the cathode electrode to a firstelectrical load outside of the fuel cell, and means to connect thesecond end of the anode electrode and the second end of the cathodeelectrode to a second electrical load.
 2. A fuel cell as in claim 1wherein the second electrical load comprises a semiconductor membrane ora diode.
 3. A fuel cell as in claim 1 wherein each of the anodeelectrode and cathode electrode have a composite cubical or cylindricalconstruction comprising an outer conductor current collector orcollectors and a catalyst coating applied to its or their surfaces andan inner current collector electrically connected to the two outerconductor current collectors through an ionic or semiconductor membranewherein the outer conductor current collector or collectors comprise thefirst end of the respective electrode and the inner current collectorcomprises the second end of the respective electrode.
 4. A fuel cell asin claim 1 wherein the anode tank and the cathode tank are separated bya common wall and the central collectors of the anode electrode and thecathode electrode are partially or completely connected through thecommon wall by an ionic or semiconductor membrane or a diode.
 5. A fuelcell as on claim 1 wherein the means to supply electrolyte to the anodetank comprises the means to withdraw electrolyte from the cathode tank.6. A fuel cell as on claim 1 wherein the means to supply electrolyte tothe cathode tank comprises the means to withdraw electrolyte from theanode tank.
 7. A fuel cell as in claim 1 further including a reactiontank and wherein the respective means to supply electrolyte to the anodetank and to the cathode tank comprise means to withdraw electrolyte fromthe reaction tank and the means to withdraw reacted electrolyte from theanode tank transfers reacted electrolyte to the reaction tank and themeans to withdraw reacted electrolyte from the cathode tank transfersreacted electrolyte to the reaction tank.
 8. A fuel cell as on claim 1further including means for recovering excess fuel from the reactedelectrolyte discharged from the anode cell.
 9. A fuel cell as in claim 1further including a means of removing reaction products from the anodetank, the cathode tank, or the reaction tank.
 10. A fuel cell as inclaim 1 further including means to raise and maintain the pressure inthe anode tank, the cathode tank, or the reaction tank to apredetermined pressure.
 11. A battery of fuel cells comprising aplurality of fuel cells as in claim 1 wherein the anode electrodes andthe cathode electrodes of adjacent cells are electrically connected inseries or in parallel.
 12. A fuel cell as in claim 1 wherein the anodeelectrode and the cathode electrode are electroplated, sputtered orcoated with a catalyst selected from the group consisting of platinum,nickel, cobalt, lithium, lanthanum, strontium, palladium, rhodium,yttrium, and mixtures thereof.
 13. A fuel cell as in claim 1 wherein theelectrolyte is a liquid electrolyte selected from the group consistingof acidic electrolytes, alkaline electrolytes, molten electrolytes. 14.A fuel cell as in claim 1 wherein the electrolyte includes modifiers inthe form of ions or colloids, said modifiers being selected from thegroup consisting of surfactants and metal ions.
 15. A fuel cell as inclaim 1 further including means to heat or cool the anode tank, thecathode tank, or the reaction tank to a predetermined temperature.
 16. Afuel cell as in claim 1 wherein the fuel is selected from the groupconsisting of hydrogen, natural and refined gaseous hydrocarbons, liquidhydrocarbons, alcohols, and natural and manufactured carbohydrates. 17.A fuel cell as in claim 1 wherein the fuel is a hydrocarbon and furtherincluding means of cracking the hydrocarbon fuel or means of forminghydrogen from hydrocarbon fuels before introducing the fuel into theanode tank.
 18. A fuel cell as in claim 1 wherein the fuel is ahydrocarbon and further including means to treat the hydrocarbon fuelprior to direct feeding to the fuel cell, the means to treat thehydrocarbon fuel being pyrolysis with or without catalysis, contactingwith a catalyst, contacting with a super acid or zeolite.
 19. A fuelcell as in claim 1 wherein the oxidant is selected from the groupconsisting of air, oxygen, oxygen-nitrogen mixtures, oxygen-carbon oxidemixtures, hydrogen peroxide, and potassium permanganate.
 20. A fuel cellas in claim 1 further providing means for intermittent injection of agaseous fuel oxidant respectively into the anode or cathode tanks.
 21. Afuel cell as in claim 15 wherein said predetermined temperature is fromsub-zero temperatures to 1200° C.
 22. A fuel cell as in claim 15 whereinsaid predetermined pressure is from sub-atmospheric to 5000 pounds persquare inch.
 23. A fuel cell as in claim 13 wherein the acidicelectrolyte is selected from the group consisting of sulphuric acid,phosphoric acid, and methane sulphonic acid, the alkaline electrolyte isselected from the group consisting of sodium hydroxide and potassiumhydroxide, and the molten electrolyte is lithium-potassium carbonate.24. A fuel cell as in claim 14 wherein the metal ion is vanadium oxide.25. A fuel cell as in claim 16 wherein the natural and refined gaseoushydrocarbon is selected from the group consisting of methane, ethane,propane, and butane, the alcohol is selected from the group consistingof methanol and ethanol, and the natural and manufactured carbohydrateis biomass gas.
 26. A fuel cell having a separate anode cell and aseparate cathode cell and a reaction vessel wherein: the anode cellcomprises an anode tank having an anode electrode immersed therein, theanode electrode is selected from a monolithic electrode, a compositeelectrode, or an internally coupled electrode, the fuel cell furthercomprises means to supply electrolyte to the anode tank from thereaction vessel, the fuel cell further comprises means to supply fuel inthe form of gas, liquid, or solid mixed with the electrolyte beingsupplied to the anode tank, the cathode cell comprises a cathode tankhaving a cathode electrode immersed therein, the cathode electrode isselected from a monolithic electrode, a composite electrode, or aninternally coupled electrode, the fuel cell further comprises means tosupply electrolyte to the cathode tank from the reaction vessel, thefuel cell further comprises means to supply air, oxygen, oroxygen-nitrogen mixtures, mixed with the electrolyte to the cathodetank, the fuel cell further comprises means to withdraw reactedelectrolyte from the anode tank and deliver to the reaction vessel, thefuel cell further comprises means to withdraw reacted electrolyte fromthe cathode tank and deliver to the reaction vessel, each of the anodeelectrode and the cathode electrode has a first end and a second end,the fuel cell further comprises means to connect the first end of theanode electrode and the first end of the cathode electrode to a firstelectrical load outside of the fuel cell, and the fuel cell furthercomprises means to connect the second end of the anode electrode and thesecond end of the cathode electrode to a second electrical load.
 27. Afuel cell as in claim 26 wherein the anode tank and the cathode tank areseparated by a common wall and the central collector of the anodeelectrode and the cathode electrode are partially or completelyconnected through the common wall by an ionic or semiconductor membraneor a diode.
 28. A fuel cell as in claim 26 wherein the second electricalload comprises semiconductor membrane or a diode.
 29. A fuel cell as inclaim 26 wherein each of the anode electrode and cathode electrode havea composite cubical or cylindrical construction comprising an outerconductor current collector or collectors and a catalyst coating appliedto its or their surfaces and an inner current collector electricallyconnected to the two outer conductor current collectors through an ionicor semiconductor membrane wherein the outer conductor current collectoror collectors comprise the first end of the respective electrode and theinner current collector comprises the second end of the respectiveelectrode.
 30. A continuous process for producing electric power andheat in a fuel cell from reacting a fuel in an anode tank and an oxidantin a cathode tank, the fuel cell having an anode electrode immersed inan electrolyte in the anode tank and a cathode electrode immersed in anelectrolyte in the cathode tank, and the anode electrode and the cathodeelectrode connected to a first electrical load at one end thereof andconnected to a second electrical load at another end thereof, theprocess comprising: introducing the fuel with the electrolyte in theanode tank wherein a catalyst on the anode electrode in the anode tankcauses a chemical reaction or ionizes the fuel thereby which produceselectrons, transferring the electrons through an external electricalload to the cathode electrode, introducing the oxidant mixed with theelectrolyte into the cathode tank wherein a catalyst on the cathodeelectrode causes a chemical reaction or ionizes the oxidant with theelectrons from the anode, and connecting the anode electrode and thecathode electrode to a second electrical load.
 31. A process as in claim30 wherein the anode tank and the cathode tank are separated by a commonwall and the central collector of the anode electrode and the cathodeelectrode are partially or completely connected through the common wallby an ionic or semiconductor membrane or a diode.
 32. The process as inclaim 30 wherein ions produced at the anode electrode required for thereaction at the cathode electrode are delivered continuously through theelectrolyte.
 33. The process as in claim 30 wherein ions produced at thecathode electrode required for reactions at the anode electrode aredelivered continuously through the electrolyte.
 34. The process as inclaim 30 further including a step of transferring the electrolyte fromthe anode tank and from the cathode tank to a reaction tank andtransferring the electrolyte from the reaction tank to the anode tankand to the cathode tank and wherein the ions produced at the anodeelectrode and the ions produced at the electrode cathode are deliveredcontinuously through the electrolyte to a reaction tank.
 35. The processas in claim 30 further including the step of recycling excess fuelexiting from the anode tank.
 36. The process as in claim 30 furtherincluding the step of removing reaction products from the electrolyte inan evaporating tank, vacuum vessel, or an absorption vessel.
 37. Theprocess as in claim 30 further including a step of injecting gaseousfuel to the anode in a cyclic manner and injecting gaseous oxidant intothe cathode tank in a cyclic manner.
 38. The process as in claim 30where the anode tank, the cathode tank, and the reaction tank are heatedor cooled.
 39. The process as in claim 30 where the anode tank, thecathode tank, and the reaction tank are pressurised.
 40. The process asin claim 30 wherein the oxidant is selected from the group consisting ofair, oxygen, oxygen-nitrogen mixtures, oxygen-carbon oxide mixtures,hydrogen peroxide, and potassium permanganate.
 41. The process as inclaim 30 wherein the fuel is selected from the group consisting ofhydrogen, natural and refined gaseous hydrocarbons, liquid hydrocarbons,coal, alcohols, and natural and manufactured carbohydrates.
 42. Theprocess as in claim 41 where the fuel is a hydrocarbon fuel and thehydrocarbon fuel is subjected to pyrolysis, contact with super acid orzeolite, cracking, gasification, or water-gas reaction to producehydrogen gas which is fed as fuel to the fuel cell.
 43. The process asin claim 30 wherein the fuel travels co-current or counter-current tothe electrolyte in the anode tank and the oxidant travels co-current orcounter-current to the electrolyte in the cathode tank.
 44. The processas in claim 30 wherein the electrolyte is a liquid electrolyte selectedfrom the group consisting of acidic electrolytes, alkaline electrolytes,molten electrolytes.
 45. The process as in claim 41 wherein the naturaland refined gaseous hydrocarbon is selected from the group consisting ofmethane, ethane, propane, and butane, the alcohol is selected from thegroup consisting of methanol and ethanol, and the natural andmanufactured carbohydrate is biomass gas.
 46. The process as in claim 44wherein the acidic electrolyte is selected from the group consisting ofsulphuric acid, phosphoric acid, and methane sulphonic acid, thealkaline electrolyte is selected from the group consisting of sodiumhydroxide and potassium hydroxide, and the molten electrolyte islithium-potassium carbonate.
 47. The process as in claim 36 wherein thereaction product is water or carbon dioxide.
 48. A fuel cell as in claim30 wherein the second electrical load comprises semiconductor membraneor a diode.
 49. A process as in claim 30 wherein each of the anodeelectrode and cathode electrode have a composite cubical or cylindricalconstruction comprising an outer conductor current collector orcollectors and a catalyst coating applied to its or their surfaces andan inner current collector electrically connected to the two outerconductor current collectors through an ionic or semiconductor membranewherein the outer conductor current collector or collectors areconnected to the electrical load and the inner current collector of therespective electrodes are connected to complete the electronic circuit.